Hey guys, so I don't see much talk about these on here I'm gonna go ahead and give my unbiased opinion so that it might help someone down the line. Long story short I have owned 2 350z's before my 370z, both of which were models equipped with LSD. My 370z is a base model...no LSD as I found out after trying to drift an turn and ending up in ditch
After that I knew I needed LSD so I began searching, found the cheapest option, which happened to be the Tomei. Saw that it came with 3.9 final drive ratio for less than other differentials without the gears so it was no brainer.
Getting it installed: this was fairly easy just need to order to "Carrier bearings" from Nissan, don't have the part number sorry.
Break in: 30 minutes of doing figure eights in a parking lot introduce you to the "Clutch" in clutch type differential. This LSD will dramatically change the way the car handles. You will be able to feel the wheels locking and unlocking. This will be a deal breaker for most, but some will be able to put up with it and eventually learn to drive it at slow speeds normally without the wheels hopping or the diff popping when the clutch engages and disengages the lock.
The 3.9 gears: My god what a difference. This might be the most slept on mod "bang for buck" wise this blows an exhaust and intake out the water. I am putting busses on other FBO z's,3.8 genesis, I am even pulling on the new 400hp 3.0tt q50's...up until the top of 3rd then that boost hits. Regardless the fact that this simple mod, as well as, Berk HFC and AAM Shorty's allows me to be pulling with a 400 hp twin turbo'd car speaks for itself.
Daily driving: This will take some time getting used especially the turning because the LSD is a clutch type LSD you will feel this in the steering wheel and how the car behaves. However, what you will also notice is the sense of security this LSD provides while driving, especially in wet conditions. This car went from being a death trap as an open differential to a safety net with this LSD. In the pouring rain I don't have any traction issues doing 80mph on the highway, with old tires! The LSD acts like traction control by itself, combine that with the 3.9 gearing and you have a car that can take any corner and attack it on approach and exit. Versus the base model car you started with that wants to spin out in a circle while cornering... just my two cents since no one really goes this route .